Biocatalysis in the Recycling Landscape for Synthetic Polymers and Plastics towards Circular Textiles

Abstract

ical-assisted depolymerization of plastics so far only works for polyethylene terephthalate, with degradation of a few other relevant synthetic polymer chains being reported. In contrast, by analyzing market data and emerging trends for synthetic fibers in the textile industry, in combination with numbers from used garment collection and sorting plants, it was shown that the use of difficult-to-recycle blended materials is rapidly growing. If the lack of recycling technology and production trend for fiber blends remains, a volume of more than 3400 Mt of waste will have been accumulated by 2030. This work highlights the urgent need to transform the textile industry from a biocatalytic perspective.

Mechanism-Based Design of Efficient PET Hydrolases

“…Aside from the well-engineered frameworks such as Pseudomonas putida, E. coli, and P. pastoris , − I. sakaiensis has recently emerged as a new promising strain for genomic engineering with considerably high conversion efficiency from PET substrates to PHA biopolymers. , On the other hand, thermophilic whole-cell biocatalysts such as Clostridium thermocellum can be easily employed for faster PET depolymerization, for example, targeting textile waste also containing cellulose, which may be degraded and valorized simultaneously. , For more details regarding the biotechnological potential of enzymatic textile recycling, readers are referred to a recent comprehensive review by Jönsson et al In this regard, designing the PET degrading multienzyme complex by combining the advantages of various enzyme classes to resemble an architecture similar to the natural cellulosome might be a viable option …”

Highly Crystalline Post‐Consumer PET Waste Hydrolysis by Surface Displayed PETase Using a Bacterial Whole‐Cell Biocatalyst

“…PET waste is currently not recycled when certain minimum requirements are not met, e. g. when the intrinsic viscosity is too low or the dye content is too high [7] . Other sources of PET waste are fibres from the textile industry, which are often blends of different materials, opening up the need for a selective depolymerisation of the individual components [8] . In recent years, the biological degradation of PET has emerged as a potential new strategy for an environmentally friendly recycling that could allow the utilization of such under‐valorized sources of PET waste as well [8,9] …”

Synthesis and melt-spinning of partly bio-based thermoplastic poly(cycloacetal-urethane)s toward sustainable textiles

“…[15][16][17][18][19] This demand is particularly important in applications where the polymer materials are complex and challenging to recycle. 20,21 Textiles are among such applications, where fibres and yarns usually contain complex materials and additives and are thus not usually recycled. 22 Therefore, new bio-based polymer fibres with improved recyclability are attractive for sustainable textiles.…”

“…23,24 To recycle complex polymer mixtures as textiles, chemical recycling is considered more practical than conventional mechanical recycling. 20,22,25 In this context, polymers with acidsensitive acetal bonds (polyacetals) are particularly attractive, [26][27][28][29] because they can be conveniently acidhydrolyzed which can enable chemical recycling even from complex textiles. 25 Polyacetals exist widely in nature, including cellulose, hemicellulose, starch, chitin, etc.…”